This invention relates generally to an improved connector for use with clamps for maintaining work-pieces in a stationary hold-down position. More particularly, the invention relates to a connector for use with a screw clamp having a work-piece contacting pad which permits both rotating and swivelling of the pad and, in certain embodiments, facile connection and disconnection of the pad from the clamp.
Wide use is made in industry of clamps for maintaining work-pieces stationary to permit the carrying out of various operations on them. The clamps usually consist of a generally C-shaped frame having a fixed pad for engaging a work-piece formed on one leg and a bolt threaded for axial movement received in an aperture formed in the other opposed leg, said bolt having a pad connected by a swivel to the free end thereof. The clamp frame alternatively can comprise an L-shaped frame having a leg slidably mounted on the shank of the frame perpendicular to the shank and parallel to the fixed leg of the frame. A fixed pad for engaging a work-piece is formed at the end of the fixed leg and a pad is connected by a swivel to the end of a bolt threaded into the movable leg.
To engage a work-piece, the movable leg of the clamp is adjusted, if slidably adjustable, so that the work-piece may be accommodated in the space between the fixed pad and swivel pad and, in both the foregoing embodiments, the threaded bolt is rotated to bring the swivel pad into abutment with the work-piece which is held against the fixed pad.
A serious shortcoming of such clamps is that there is no simple means by which the swivel pad can be removed from the bolt shank. When, for example, the threads of the bolt shank become clogged with weld spatter or are damaged by misuse, the bolt and swivel pad connected thereto must be discarded since there is usually no ready method of removing the pad from the bolt in a user's shop. So too must the bolt and swivel pad usually be discarded when the swivel connection between the pad and the shank is rendered inoperable because of weld spatter, dirt or other foreign material since the two elements cannot be separated to permit cleaning and lubrication of the connection.
Another shortcoming of such clamps is that special tools normally are required to attach the swivel pad to the bolt shank. Should, for example, the swivel pad accidentally separate from the bolt shank, the pad cannot usually be reattached because the user lacks the necessary swaging machinery to do so.
Detachable swivel pads are known, as shown in U.S. Pat. Nos. 260,510; 1,387,996; and 2,579,995. However, a shortcoming of such clamps is that the swivel pad is capable of only very limited tipping or pivoting, if any, and hence such clamps are not well suited to grasping irregularly shaped work-pieces commonly encountered.
It is an object of the present invention to provide a clamp having means by which a swivel pad can be readily connected to and, in certain embodiments, readily separated from the shank of a bolt without the necessity of any special tools or equipment.
It is another object of the invention to provide a clamp having a swivel pad capable of pivoting over a very wide angle and hence capable of grasping work-pieces of a variety of shapes.
And a further object of the invention is the provision of a connector for securing a pressure pad to a bolt shank which permits a wide clearance between the pad and bolt shank for easy removal of foreign material.